Procedure and reactor for destructive hydrogenation of lube oils

ABSTRACT

Destructive hydrogenation of lubricating oils by hydrogenating, hydrocracking and isomerizing oils, which have not been conditioned, in the presence of at least two layers of catalysts in a single reaction, to obtain a synergistic effect of their hydrogenating, hydrocracking, and isomerizing functions.

United States Patent Nastast et al.

[ 1 Feb. 19, 1974 PROCEDURE AND REACTOR FOR DESTRUCTIVE HYDROGENATION OF LUBE OILS Inventors: Adrian Vasile Nastast; Ion Zirna,

Assignee:

Filed:

both of Ploiesti; Ion Doru Grigoriu, Bucharest; Constantin L. Savu, Ploiesti; Corneliu Nicolae Stetanescu, Ploiesti; Dumitru C. Iorga, Ploiesti; Ion V. Ghejan, Ploiesti; Alexandru C. Platon, Ploiesti; Flavia T. Constantin, Ploiesti; Petru T. Bohiltea, Ploiesti; Stelian GH. Dumitrescu, Bucharest; [on T. Bohiltea, Cimpina, all of Romania Institutul De Cercetare Si Proiectare Tehnologica Pentru Prelucrarea Titeiului, Ploiesti, Romania Mar. 8, 1972 Appl. No.: 232,682

Foreign Application Priority Data Feb. 6, 1971 US. Cl.

Romania 65824 CWTA'LKST 4 arse -4 Primary ExaminerDelbert E. Gantz Assistant Examiner-G. E. Schmitkons Attorney, Agent, or FirmKarl F. Ross; Herbert Dubno [57] ABSTRACT Destructive hydrogenation of lubricating oils by hydrogenating, hydrocracking and isomerizing oils, which have not been conditioned, in the presence of at least two layers of catalysts in a single reaction, to obtain a synergistic effect of their hydrogenating, hydrocracking, and isomerizing functions.

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PROCEDURE AND REACTOR FOR DESTRUCTIVE HYDROGENATION OF LUBE OILS FIELD OF THE INVENTION The present invention refers to a procedure and reactor for the destructive hydrogenation of lubricating oils, in order to obtain lubricants, in one or more cuts, having a high viscosity index.

BACKGROUND OF THE IN VENTION There are known methods of improving the quality of lubricating oils by the selective extraction of a feedstock. These methods mostly used today in petroleum processes have a limited capacity for economically increasing the viscosity index. In the petroleum industry, the quantity of waxxfree crude oils, which is not suitable for obtaining premium grade lubricating oils, is continually increasing. Obtaining oils having a high viscosity index from these crude oils by the methods of selective extraction is quite impossible.

Other known methods of improving the quality of lubricating oils involve hydrofining the feedstocks treated with hydrogen. These methods, however, do not change the viscosity index of the processed products. The catalysts used in the hydrofining processes do not have a cracking function, so that, as a rule, the aromatic hydrocarbons are not changed into condensed naphthenes, which should be hydrocracked selectively in order to produce alkyl-naphthenes with a high viscosity index. Also, these catalysts do not isomerize the paraffin hydrocarbons.

There are known methods of destructive hydrogenation of lubricating oils, applied recently in industry, which eliminate selective extraction and hydrofining, and achieve yields more or less comparable with the latter, changing the distilled oils into oils with a high vicosity index, without conditioning the feedstock. These methods are based on contacting the feedstock with the hydrogen on a layer of specific catalyst which has the same structure along the whole reaction zone. However, the methods of destructive hydrogenation of lubricating oils do not achieve a significant increase in the viscosity index at a high yield; a steady average increase in this characteristic is difficult to obtain since only one catalyst is used in the reactor, thus not creat-' ing the possibility of an synergistic action of the functions' of hydrogenation, hydrocracking and isomerization in the reactor, in the presence of the appropriate catalysts.

DESCRIPTION OF THE INVENTION Destructive hydrogenation of lubricating oils, according to the invention, eliminates the above disadvantages and achieves relatively high yields of hydrotreated products with a substantial increase in the viscosity index, without conditioning of the feedstock, by means of two or more distinct layers of two specific and different catalysts, set out in the same reactor; the first catalyst has the prevalent function of hydrogenation, and the second one has the prevalent function of hydrocracking-isomerization, functions that are carried out in relation to the active element composition of the catalysts and/or acidity of their support ensuring taking over of heat from the reaction of hydrogen and/or hydrocarbon fractions. The reactor for this procedure is a cylindrical vessel made up of two or more successive reaction zones in which there are two or more succeslit sive and distinct layers, even or uneven, formed of two catalysts, specific or different. Separating the zones are one or more sieves of the fractionating-tray type without downeomers; a coaxial cooling system formed of two or more pipelines for feeding every reaction zone in the cooling point, with hydrogen and/or hydrocarbon fractions is also provided.

DESCRIPTION OF THE DRAWING FIG. 1 is a schematic diagram of the reactor operating with only two catalyst layers;

FIG. 2 is a graph showing results obtained.

FIG. 2 represents the variation of the viscosity index and the viscosity of hydrogenated oil, obtained in accordance with the invention (curves [1 and as compared to the same elements obtained with type A catalysts (curves -0-) and and B type (curves A and catalysts when used separately in the reactor. Catalyst A is a nickelmolybdenum catalyst, and catalyst B is a nickeltungsten catalyst. By proper selection of the operating conditions, at the same yield of oil, the viscosity index of the oil resulting from the invention is, in all cases, higher than when type A and type B are used separately; in addition, at the same viscosity index, the highest yields result when following the procedure of this invention.

SPECIFIC DESCRIPTION SPECIFICEXAMPLES Example 1 The feedstock, a distilled oil of naphthenic-aromatic type, having the viscosity: 30E/50C and viscosity index: 45, together with the addition and recycle of hydrogen, is fed to the reactor with a space velocity of 0.5 vo1./vol. hr., under a pressure of atm. and a recycle ratio of 1500 m3/m3 STP and are passed downfiow through two distinctive layers of specific and different catalysts of A and B type. Thus are obtained the improvements of the viscosity index, decoloration, sweet ening, denitrification, carbon residue reduction, and demetallization. Cooling of the reaction zone is done with hydrogen. After the rich gases have been removed from the reaction product, the liquid product is stripped in order to remove the hydrogen sulphide and gases, and then fractionated to separate the light and medium products. The bottom product lubricating oil is then vacuum-distilled in order to obtain different qualities of oils.

The lubricating oil fraction obtained when operating at 415C temperature has the characteristics given below in Table 1.

TABLE 1 Characteristics Values Yield, wt. 66 (oil within the same distillation range as the feedstock) TABLE l-Continued Characteristics Values Viscosity Index 100 Viscosity, E/50C 6.4

EXAMPLE 2 The same feedstock is used under the same conditions as above at the reaction temperature of 420C.

The unit lubricating oil fraction obtained has the following characteristics:

TABLE 2 Characteristics Values Yield, wt. 62 (oil with the same distillation range as the feedstock) Viscosity index 102 Viscosity, Ii/50C 6.2

EXAMPLE 3 TABLE 3 With Atype catalyst Temperature, "C (reaction) Yield, wt.

(oil with the same distillation range as the feedstock) Viscosity index Viscosity, E/50C 9 TABLE 4 With B-type catalyst Temperature, "C (reaction) Yield, wt.

(oil with the same distillation range as the feedstock) Viscosity index Viscosity, E/50C Table 5 shows that the procedure followed according to the invention yeidls a product of the highest viscosity, at the lowest operating temperature for an oil of vistemperature, C

TABLE 5-Continued 5 Characteristics Values With B-type catalyst As per invention Yield, wt. (oil with the 1 same distillation range as the feedstock) Viscosity, E/50C By a proper selection of the operating conditions, at the same yield of oil, the viscosity index of the lubricating oil is, in all cases, higher than in the cases where A and B type catalysts are used separately, and at the same viscosity index, the highest yields are also obtained in the case of the procedure as per invention. The procedure and reactor, according to the invention, have the following advantages:

They lead to a synergetic action of the catalysts employed so that a higher viscosity index is obtained at relatively high yields of product.

High-quality products should be obtained under milder conditions.

They offer the possibility of guiding the reactions so that depending upon the quantity, activity and selectivity of the catalysts employed, premium grade products can be obtained as required.

We claim: l. A process for the destructive hydrogenation of a lubricating oil comprising the steps of:

selectively hydrogenating polycyclic aromatic compounds in the lubricating oil by passing same in the presence of hydrogen at a temperature of about 410 to 440C and a pressure of about l50 to 180 first catalystlayer in a reactor; passing in the same reactor the selectively hydrogenated lubricating oil through a nickel-tungsten sec- 0nd catalyst layer distinct from the first at a temperature of about 410 to 440C and at a pressureof 150 to 180 Atm; and without separation of the reaction product obtained upon passage of the lubricating oil through the first layer for the hydrocracking and isomerization of components of the lubricating oil; and

stripping gases from the reaction product emerging from the second layer and fractionating the liquid phase thus recovered.

2. The process defined in claim 1 wherein hydrogen .is recovered from said reaction product in the stripping of gas therefrom and is recirculated to the hydrogenation of the lubricating oil at a recycle ratio of about l,500 rn (STP) per m the oil being provided at said first layer at 'a space velocity of 0.5 to l volume/hour/- reactor volume.

Atm downwardly through a nickel-molybdenum 

2. The process defined in claim 1 wherein hydrogen is recovered from said reaction product in the stripping of gas therefrom and is recirculated to the hydrogenation of the lubricating oil at a recycle ratio of about 1,500 m3 (STP) per m3, the oil being provided aT said first layer at a space velocity of 0.5 to 1 volume/hour/reactor volume. 